The present invention relates to roofing systems utilizing flexible roofing sheets.
The most generally known and used methods of applying flexible roofing sheets to supporting structures involves positioning the sheets against the supported structure and then securing the sheets by driving a headed fastener such as a screw through the sheet into the supporting structure or running a series of battens overlying the membrane in parallel to the edge of the roof and then driving a headed fastener such as a nail through the batten and sheet and into the supporting structure. There are many problems associated with these methods, some involving maintaining an effective weather seal around the nail, some relating to the relatively slow process of positioning and driving nails through the sheet or batten into the support structure, and others having to do with the effective dispersion of wind uplift forces under which certain high wind conditions may subject opposed inside and outside surfaces of a given roof to pressure differentials wherein wind forces create vacuum zones on the outside roof membrane. Under such high wind conditions, relatively positive high pressure may occur under the roof membrane by air infiltration into gaps under the membrane, when compared to the existing atmospheric pressure exerted on the exterior of a roof membrane. Such positive pressure has been known to blow the roof membrane from its support structure. In connection with this latter point, it has been determined that the conventional method of applying a series of battens in parallel to the edge of a roof essentially seals off interior areas of a roofing installation. Such interior areas are subject to wind uplift conditions which create pressure differentials to cause tearing of the membrane around the batten or the batten itself being blown off the roof. These results cause unnecessary waste and undesirable replacement costs.
It is therefore an object of the present invention to provide a means and method for controlling ballooning in a roofing system.
It is another object of the present invention to provide a means and method for equalizing air pressure in a roofing system.
It is a further object of the present invention to provide an improved method for installing a roofing system.
Other objects will be in part obvious and in part pointed out in more detail hereinafter.
A better understanding of the objects, advantages, features, properties and relations of the invention will be obtained from the following detailed description and accompanying drawings which set forth certain illustrative embodiments and are indicative of the various ways in which the principles of the invention are employed.